China announces plan to build early-warning system for dangerous asteroids

China has announced that it wants to develop a "space-ground" asteroid early-warning network, while providing few details on what it could look like. But recent papers and presentations to the United Nations provide clues as to what the country has in mind for planetary defense.

The China National Space Administration (CNSA) made the announcement on June 30 — International Asteroid Day — stating plans to construct a coordinated ground-and-space monitoring system for near-Earth asteroids. Li Mingtao, chief scientist at CNSA's Asteroid Monitoring and Early Warning Research Center, told state media that China is studying the feasibility of an asteroid defense system, with the ground-space monitoring network as its core.

"No asteroid has so far been identified that will definitely collide with Earth in the foreseeable future, but concerns over impact risks are not unfounded. Many near-Earth asteroids remain undetected," the state-run media outlet Xinhua quoted Li as saying in a report by Science and Technology Daily.

Li added that China will deploy multiple large-aperture optical telescopes at carefully chosen sites in order to be able to survey the sky, while adding a space-based monitoring constellation, free from atmospheric disruption and day-night constraints, with a particular focus on threats from the sunward direction, which are, from the ground, lost in the glare of the sun. The meteor that exploded over Chelyabinsk, Russia, in 2013, approached roughly from a sunward direction and was only detected once it entered the atmosphere.

Li told Science and Technology Daily that more than 40,000 near-Earth asteroids have been discovered so far, including over 95% of asteroids at least 1 kilometer (0.6 miles) wide, which are capable of causing a globally catastrophic impact. However, only around 45% of asteroids in the 140-meter (460-foot) class have been detected, which are large enough to devastate a small country.

The June 30 reports and CNSA statements were vague on what China's actual plans for its monitoring network may be. However, recent journal papers and a 2025 presentation to the U.N.'s Committee on the Peaceful Uses of Outer Space (COPUOS) give more detail on the country's thinking.

For example, a paper published in the Journal of Deep Space Exploration in June 2026, co-authored by Wu Weiren, chief designer of China's lunar exploration program and a leading voice on the country's asteroid defense plans, lays out the options under study.

For the space-based component, the paper names four candidate orbital positions for a monitoring network: the Sun-Earth L1 Lagrange point, an Earth-leading or trailing orbit, a Venus-like heliocentric orbit, and an Earth-companion distant retrograde orbit (DRO). The paper also describes ongoing research into each option's monitoring effectiveness.

A similar outline was found in a 2025 technical presentation to COPUOS by Chinese researcher Chen Yongcai. A "basic model" would consist of a single satellite at Sun-Earth L1, an orbit about 1.5 million kilometers (930,000 miles) inside that of Earth, paired with northern and southern ground stations. An "extended model" includes spacecraft in the three additional orbits stated in the Wu Weiren paper. The Venus-like option in particular closely tracks an earlier proposal known as CROWN, a constellation of small satellites in Venus-like orbits designed to survey the sunward sky and use its favorable geometry to track other populations of near-Earth asteroids.

The status and timelines of these plans are unclear, but they do indicate a clear interest in and commitment to planetary defense by China. The country's 15th Five-Year Plan, approved in March, states that an asteroid defense engineering project is under study, while China is developing a kinetic-impact and observation demonstration mission, similar to NASA's DART mission and the European Space Agency's (ESA) follow-on Hera project, which is scheduled to launch in 2027.

While China's apparent plans are not unique, they could augment global efforts. Anne Virkki, an asteroid researcher at the University of Helsinki who's familiar with international monitoring efforts, noted that NASA and ESA have plans to send missions to Sun-Earth L1 to search for asteroids in infrared light — NEO Surveyor and NEOMIR respectively.

"If China launches a similar mission, hopefully it has some capability that the other two do not, and that it shares the data internationally and not only for Chinese scientists," Virkki said.

Virkki noted that asteroids approaching from the sun's direction aren't physically unusual, but they are simply harder to track, which statistically makes them more likely to produce a surprise. She also pointed to the persistent, less-discussed gap in radar tracking capacity. That capacity took a serious hit with the 2020 collapse of the Arecibo Observatory in Puerto Rico, with no U.S. successor in the works.

China has discussed building its own radar capability, which Virkki said would be a welcome addition, provided the data is shared openly. China has built the "China Compound Eye" or Fuyan project near Chongqing in the country's southwest, which can be used for near-Earth asteroid monitoring. Wu's paper also notes ground-based radar in the proposal for asteroid monitoring.

"Hopefully, as China's planetary defense plans become more specific, we'll see telescopes and space telescopes that complement the existing or planned capabilities of other countries, rather than repeat redundantly, and contribute data openly and collaboratively," Virkki said. She noted that there are likely about 100,000 near-Earth asteroids that could cause significant local damage if they hit Earth, and we know the orbits of less than half of all such space rocks.

2029 will mark the International Year of Planetary Defense, when the infamous asteroid Apophis will fly past the Earth just within the orbit of geostationary satellites. "There is a lot of work left to do, and international collaboration is crucial," said Virkki.